One widely-available two-piece ostomy appliance (Hollister Two-Piece Ostomy System) includes a collection pouch having a channel-defining coupling ring extending about an opening in a wall of the pouch and an adhesive faceplate having a mating ring with a compressible insert portion receivable in the channel. The insert portion includes a relatively thick and rigid annular member having a tapered, deformable wiper flange that angles rearwardly and away from the front end of the annular member for resiliently and sealingly engaging one of the walls of the channel when the parts are coupled together. The opposite wall of the channel is provided with at least one bead engagable with an opposing bead projecting from the side of the annular member opposite from the deformable wiper flange. Since the width of the insert in an uncompressed state is greater than that of the channel, simultaneous latching on the bead side of the annular member and fluid-tight sealing on the wiper flange side occur when the coupling rings are fitted together.
To insure a secure fluid-tight coupling of the rings, both the compressible insert with its thin wiper flange and the walls of the channel become deformed when the parts are connected. The wiper flange is flexed towards the thick annular member to which it is integrally joined at the same time the side walls of the channel are spread outwardly so that such walls diverge in the direction of the channel entrance. One result of such coaction and the divergence of the channel walls is that the tightness of the fit between the parts will progressively diminish whenever the insert is shifted towards the channel entrance. As the tension and deformation of both the channel and the flexible wiper flange are reduced, the security of the latch and the tightness of the seal are compromised.
It is a further characteristic of such a two-piece construction that if the coupling rings are dimensioned to provide a tighter interfit and insure greater security against accidental detachment of the rings, the effort required to join the rings together is also increased. Security of attachment is therefore achieved at the expense of requiring substantial deformation of the parts during assembly, with such deformation necessitating the application of substantial coupling forces that some users, especially the elderly and infirm, may have difficulty providing.
A main aspect of this invention therefore lies in providing a two-piece ostomy appliance with coupling rings that provide a high level of security when mated together but still require relatively little effort for a user to assemble. High security is achieved because of the expansive rocking action of a non-deformable wedge body that occurs during the initial stages of ring separation. Such rocking movement effectively increases the radial width of the substantially non-compressible insert and thereby increases the resistance to ring separation. At the same time, ease of assembly is promoted because the reverse rotation of the non-deformable wedge body during a coupling operation decreases the effective width of the insert, thereby lessening deformation of the channel and reducing the force needed to urge the insert into that channel.
These results, and the differences in the manner of operation responsible for them, may be achieved by substituting only the male coupling ring (e.g., the faceplate ring) of this invention for the standard male ring of the conventional two-piece system as described above. The standard channel-providing ring (e.g., the pouch ring) may remain unchanged, although modifications of that ring may be made if desired.
Unlike prior faceplate coupling rings, the faceplate ring of this invention has an annular insert that is substantially non-compressible in radial directions and includes an axially-extending annular collar, a bulbous non-deformable wedge body of toroidal shape, and an annular radially-extending pivot stem that connects the non-deformable wedge body and the collar in concentric relation. The wedge body has a massive front portion that projects forwardly beyond the stem and a similarly massive rear portion that extends rearwardly behind the stem. A bearing surface that is provided by the front portion (also, if desired, by part of the rear portion) curves inwardly and rearwardly at progressively increasing distances from the pivot axis extending through the stem. Because of the progressively increasing radii of curvature in a rearward direction and the provision of a stem which supports the wedge body for limited rocking movement about a pivot axis, the massive non-deformable body functions as a rocking wedge that forceably increases the radial width of the non-compressible insert when the wedge body rocks forwardly and decreases such width when the wedge rocks rearwardly. Rearward rocking action occurs during insertion and forward rocking action during extraction, so the locking action is self-augmenting, automatically adjusting to reduce coupling forces during assembly while providing forceful expansion and desirably high resistance to accidental separation of the parts when they are fully connected.
Other features, advantages, and objects will appear from the specification and drawings.